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Metaxenia in apples cv. 'Rewena', 'Relinda', 'Baujade' as influenced by scab resistant pollinizers
11-14.Views:343Fruit quality of cross pollinated apples (Malus x domestica) influenced by the metaxenic pollen effect of the pollinizer was observed in Hungary. Flowers of three resistant cultivars (`Baujade', `Rewena') were hand pollinated with other resistant apple cultivars. Fruits were harvested on 25 September, 2005. Fruit quality was investigated in the laboratory of the Department of Pomology; Corvinus University of Budapest. Not only size and morphological parameters (diameter, height, stem length), but also refraction and acidic content of the fruits were measured.
According to the statistical analysis significant differences were determined on fruits among the groups as an effect of the pollen provider. In consideration of size parameters (diameter, height, weight) of `Rewena' fruits pollination partner 'Freedom' and 'Prima' caused outstanding results but `Florina' caused flatter fruits. Pollen of `Florina' and `Freedor-,' caused a higher percent refraction in the fruits of `Rewena'. In the case of `Baujade' fruits `Reglindis' — among cultivars we used as pollinizer — caused the biggest fruits medium flesh firmness and harmonic inner content values. `Rajka' caused on one hand smaller fruits and on the other hand higher flesh firmness and inner content values in the case of `Relinda' fruits. According to our data measured pollinizers varied the stem length as well.
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N:K ratio and its effect on paprika yield and quality in hydroculture
35-38.Views:162Earlier results of experiments with paprika grown in soil have shown the high sensitivity of the crop to nutrient supply. According to these findings, yield and also fruit quality are highly affected not only by the nitrogen and potassium level, the concentration of nutrient solution, but also by the nitrogen-potassium ratio. Our preliminary tests have also proved, that the composition of the nutrient solution, first of all, the N/K ratio has a definite effect on the yield quantity and quality. Therefore we have investigated the ratio of the two nutrients with the aim of developing a nutrient solution of optimal composition for white fruited paprika forcing. The most balanced burden of the plants was found when the N/K ratio was 1:1. The highest yield was produced with N/K 1:1.3. Significant yield reduction (30%) was found with the treatment N/K 1:1.9 as compared to the 1:1.3 and 1:1.6.
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Exploring and preserving old apple cultivars of the Carpathian basin
9-13.Views:184In a few scattered orchards of the Carpathian basin one can still find our most common historical apple cultivars and certain traces of traditional cultivation. We consider it an important part of the Department's breeding work to explore old apple cultivars which can be used as parent partners and sources of resistance, to identify them pomologically as well as to examine the production and marketing value of old cultivars recommended for cultivation in ecological production and in gardens. This paper documents the results of expedition and collecting work carried out in three regions of the Carpathian basin (foot of the Carpathian Mountains, Transylvania, Aggtelek karst area), and also the saving of old Hungarian apple cultivars preserved until present in the English National Fruit Collection. A total of more than 100 old apple cultivars and variations, as well as 13 valuable genotypes were collected during our explorations in the above mentioned four areas. A further aim of our work is to contribute to the protection of still savable archaic fruit production relict= areas and to the preservation of cultivars in the certain regions, and also to promote the recognition of the aesthetic landscape value of old apple trees and endemic orchards of old cultivars. Our good co-operating partners in this work are Aggtelek National Park, Farmer Club of Visk and the consultation centre of Hungarian horticulturist training beyond the border in Nyárádszereda.
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Floral phenology investigation of scab resistant apple varieties and multi-resistant candidates — bred in Hungary — in 2007-2008
7-10.Views:195Apple (Malus x domestica) is considered practically self-incompatible, polleniser is essential for its economical cultivation. When choosing a polleniser many biological and economical parameters should be taken into consideration. Scab resistant apple varieties and multi-resistant candidates — bred in Hungary — were investigated in our experiment in 2007-2008. Blooming time groups were created according to the overlap of the blooming of the varieties and candidates. Observations were set up in Szigetcsép — the Research Station of Faculty of Horticultural Science. The orchard was planted in 1997. Trees were trained to slender spindle on Rootstock M9. Varieties have been assigned four blooming time groups. 'Reglindis' started blooming in both years. Candidate MR-09 belonged to the early group in 2007 and to the mid-early group in 2008. Latest varieties are 'Freedom' and `Baujade'. Candidate MR-10 belonged to the mid-late group.
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First selections of the Hungarian apple breeding program for multiple resistance
9-13.Views:169The aim of the first Hungarian apple breeding program for multiple resistance started in the beginning of the nineties is to widen Hungarian apple assortment by good quality, resistant apple cultivars with excellent productivity and ecological capability to the most important fruit growing areas in Hungary. In the first years of seedling production we made early selection for susceptibility to apple scab in greenhouse. Alter this, field observation of susceptibility to powdery mildew, scab and canker and a yearly negative selection was carried on. From 1997, fruit quality was evaluated as well, and from 2001 the resistance of shoots to Erwinia ainylovora (Burrill/Winslow et al.) was examined using inoculations in greenhouse conditions. From the progenies of crosses in 1992 and 1993, six candidates were announced to national recognition out of hybrids examined for more than a decade. Descriptions of these selections from 'Prima' progenies and the most important data of their resistance, growing habit, morphological characteristics and fruit quality are shown in this article.
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Metaxenic pollen effect of scab resistant apple cultivars on the fruit of apple
47-52.Views:164As a part of an apple breeding program, we have examined the pollen effect on the fruit appearance and inner quality of different apple cultivars in the Corvinus University of Budapest Department of Fruit Science. Five apple cultivars ('Golden Reinders', 'Regal Prince', 'Rewena', 'Renora', 'Idared') have been crossed by the pollen of some new and some traditional cultivars in our experiment. The measurements were carried out in the analytic and fruit examining laboratory of the Department of Fruit Science. The diameter, height and stem length were measured by digital caliper. We have also examined the squash ratio, soluble solid- and acidic content. Sugar content was calculated by a schedule released by the International Sugar Committee (ISC). From the sugar- and acidic content, we could also count the Pomona-value.
We have observed interesting effects according to some attributes in some crossing combinations with the help of statistical analysis. Crossing 'Golden Delicious' with 'Freedom', 'Prima', and 'Baujade' have resulted in smaller fruit size than other combinations. No significant differences could be observed on `Golden Reinders' fruits according to metaxenic coloration in the year of the examination. On the other hand the color modifying effect of pollen donating cultivars have manifested on the red fruits of 'Regal Prince' (Gala Must). `Freedom' as a pollen donating cultivar has resulted outstanding value in our consistency measurements. Squash ratio was the highest in combinations pollinated by 'Prima' and `Reglindis'. We have noticed balanced values when measuring inner qualities, only `Reka' has caused lower acidic content. Significant differences have been found in combinations according to the number of frivolous seeds. No frivolous seeds were found in the combinations 'Golden Reinders' x 'Freedom' and 'Idared' x 'Prima'. Almost two frivolous seeds were found in the fruits of the combination 'Renora' x 'Sóvári' in average.
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Flower visiting activity of honeybees on fruit species blooming subsequently
12-16.Views:196In the small demonstration orchard of the College Faculty of Horticulture at Kecskemét the blooming time, the flower density and the honeybee activity was observed at a number of cultivars of 20 flower species during four consecutive years.
Fruit crop species were in flower during 3-4 months altogether. The blooming period of them was classified into five groups as early (almond, apricot, gooseberry), middle early (sweet cherry, red currant, currant-gooseberry, black currant, white currant, peach, plum, sour cherry), middle late (pear, strawberry, apple), late (black elder, quince, medlar, raspberry, blackberry-raspberry) and very late blooming period (blackberry). The blooming period of the members of the groups of early and medium early blooming often coincided partly and the same happened between the medium and the medium late as well as between fruits of late and very late flowering.
The flower density of some fruit species is extremely variable (currant-gooseberry, medlar), while at others it is fairly stable and evenly dense in consecutive years (sour cherry, sweet cherry, strawberry). At other fruit species it is moderately changeable. Some fruit species tended to attract more honeybees than others (plum, apple, quince, medlar) and some of them tended to attract much less (black elder, pear) but most species can be regarded as of medium attractivity.
On the flowers of some fruit species (pear, strawberry, quince) honeybees gathered pollen predominantly. At most fruit species however pollen and nectar gathering behaviour seemed to be gradually changing during the season. Namely most honeybees tended to gather pollen at the flowers of the early blooming fruit species, but on the other hand typical foraging behaviour gradually shifted to nectar gathering at the flowers of fruit species of moderate and late blooming periods.
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Effect of Erwinia amylovora infection on peroxidase enzyme activity in resistant apple cultivars
37-39.Views:159Two apple cultivars that display enhanced resistance to fire blight (causal agent: Erwinia amylovora) were selected. The aim of the present study was to characterize the peroxidase (POD) enzyme activity of `Szemes alma' (a historical cultivar) and MR-03, (a Hungarian multiresistant hybrid of 'Prima') and compare them to susceptible 'Jonathan M 40' and resistant 'Remo' controls. Peroxides enzyme activity during E. amylovora infections was investigated in artificially infected apple shoots. Increases in enzyme activities were observed in a `Jonathan M40' and in 'Remo', MR-03, `Szemes alma' cultivars. There was a consistent relationship between total enzyme activity and fire blight disease severity. High activity of the peroxidase was positively correlated with the degree of resistance to fire blight. A general hypothesis that POD activity is related to fire blight susceptibility/resistance is supported by our results.
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Frost induced changes in enzyme activities and carbohydrate content in the spurs of some pear cultivars during the dormancy
41-44.Views:226Frost tolerance of pear cultivars was checked after artificial cold treatment in 2003-2005. Limbs collected during the endodormancy were exposed in a climatic chamber for 24 hours to —25; —28 °C, while those collected in the ecodormancy were kept at —15 and —18 °C. Frost damages of buds were registered according to a visually defined scale, then peroxidase (POD), polyphenol oxidase (PPO) enzyme activities and carbohydrate contents were checked in buds and spur-part below the buds. POD activity of untreated control in tissue below buds was higher than in the buds, which were increasing continuously during the endodormancy and decreased at the end of the ecodormancy. During endodormancy, cold treatment of —25 and —28 °C effected different changes of enzyme activity in buds of the cultivars. In the ecodormancy, enzyme activities increased after a cold treatment of —15 °C, whereas the activities decreased significantly after —18 °C. `Kaiser' — susceptible to frost — with its higher values of both enzyme activities marked out from other cultivars, which is correlated with its stress response. Changes in carbohydrate components — especially in glucose — of buds monitored well the different stress responses of tolerant and resistant pear cultivars induced by frost stress.
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Scab resistance in Malus sp. progenies - inheritance and resistance stability
9-15.Views:166Susceptibility of progenies of some Ma/us species to apple scab was evaluated. Susceptibility of hybrid families was observed first in greenhouse after artificial inoculations by the suspension of the pathogen, Venturia inaequalis (Cooke) Wint., then in open field. The Hungarian type of Malus floribunda, which proved to be scab resistant in our examinations, has a positive effect on the segregation of progenies to resistant and susceptible individuals as a male parent, not depending on the rate of susceptibility of the other parent. However, the German type of Malus floribunda and Malus prunifolia act as dominant, highly susceptible parents.
Malus x purpurea and Malus baccata, which proved to be highly susceptible to apple scab in open field and in artificial inoculations, transmits its susceptibility only slightly to its progenies as a male parent.
According to our experiments, the inheritance of scab resistance of Malus floribunda cannot be considered as monogenic, as published by other authors.
Scab susceptibility of parents influences the segregation of progenies to resistant or susceptible individuals. The moderately scab susceptible `Idared' as female parent has a statistically proved positive effect on the segregation of its progenies.
More factors indicate the appearance of a new race of Venturia inaequalis (Cke.) Wint.: change of the symptoms in the greenhouse; considerable increase of susceptible individuals after greenhouse inoculation in 1997; more and more progenies of the male parent Malus floribunda became susceptible to scab in open field.
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Chemical communication with volatile semiochemicals in Phyllotreta species (Coleoptera, Chrysomelidae): a minireview
93-100.Views:205Phyllotreta species (Coleoptera, Chrysomelidae, Halticinae) rank among the most important horticultural pests in the Northern Hemisphere. Leaf damage caused by flea beetles upsets the water balance, blocks plant growth and sometimes causes a high level of mortality of seedlings. Several species are known to act as vectors of numerous pathogens as well. Chemical communication plays an important role in the host finding, feeding and oviposition behaviour of flea beetles. In the first phase volatile mustard oils (isothiocyanates and thiocyanates) are released from the host plants through the decomposition of non-volatile glucosinolates (chemicals specific to Cruciferae) by myrosinase, and beetles are attracted to the source of release from a distance. Among the isothiocyanates, allyl isothiocyanate is the longest known and widespread compound utilized in the host-plant location of Phyllotreta species, but some species may have a stronger preference to other isothiocyanates or thiocyanates. The attractive effect of the plant volatiles is enhanced by the emission of a male-produced aggregation pheromone. The presence of such a pheromone was first demonstrated in Phyllotreta cruciferae Goeze. In this species R5R,5aS)-1,1,5,8-tetramethy1-1,2,3,4,5,6,5a-heptahydrobenzo[1,2-a][7]annulene] was found to be the main pheromone component. Significant attraction by the pheromone was recorded only in the presence of ALLYL ITCN. The biological activity of the pheromone compound was connected to the plus (+) chirality. The same component seems to be occurring also in the pheromones of several other Phyllotreta spp. as well, suggesting a wider occurence in the genus. Once attracted by the joint effect of plant volatiles and aggregation pheromone, the presence of the non-volatile glucosinolates in the plant tissues is necessary for continuous feeding. Aggregations of flea beetles on suitable host plants, which result from the joint effects of plant-derived and pheromonal chemical cues detailed above may also be good rendez-vous occasions, increasing the probability of encounters with the opposite sex and mating in the vicinity of the optimal oviposition site. Due to the horticultural importance of Phyllotreta spp., deciphering details of their chemical communication has considerable significance in the development of new methods of integrated control.
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Comparison of propagation methods of different moss species used as wall and ground covering ornamental plants
57-63.Views:552Mosses are traditionally used as ornamental plants, especially in Japan, USA, England (moss gardens) and Germany, French (green roofs). In shadow areas (where the members of Poaceae usually cannot grow well), mosses are potentially use as “grass”. The stocks of moss colonies maintain optimal microclimate and decrease desiccation of soils (like mulch). Additionally, mosses are evergreen, attractive all year, during winter. In our study, 18 moss species were propagated by fragments (as mixture, with the use of 16 species) and transplantation of carpets (with Brachythecium rivulare and Calliergonella cuspidata) in Szentendre. The aim was to find the most durable species and the best way of propagation. In an outdoor, irrigated garden, propagation by fragments was effective (with 63% coveration) and higher values (93% and 76%) were obtained in the cases of non-irrigated stocks of Amblystegium serpens (in trays) and moss carpets. In vertical structures (moss picture-frames with the use of mixtures), protonema of 2 species (Hypnum cupressiforme and Eurhynchium hyans) covered 24 and 33% of the 0.5 x 0.5 m sized area.
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Floral biological investigations of apple cultivars in relation to fire blight
9-14.Views:177Floral activity was studied in two apple cultivars: an Erwinia-tolerant (Treedorn') and a sensitive one (`Sampion'). Since more types of protogyny occur in apples, the period of stigma activity is different. Papillae of the exposed stigma in flowers of 'Freedom' function longer (usually more than a week) than in the delayed homogamous `Sampion'. Despite of this, cv. 'Freedom' is tolerant to Erwinia amylovora (Burr.) Winslow et al., suggesting no relationship between the floral biological type (including the exposure and longevity of stigma) and the infection by E. amylovora. According to SEM micrographs, nectary stomata in `Freedom' are already open in the flower bud, where nectar secretion starts and continues until the senescence of the stigma. However, the long period of nectar secretion does not create optimal conditions for bacterial growth, since nectar production is scant in the flowers of 'Freedom'. The surface of the nectary, its nectar-retaining capacity, and the amount and concentration of nectar may influence the susceptibility of apple cultivars. It is manifested well by the smooth nectary surface with nectary stomata rising slightly above the epidermis in flowers of cv. 'Freedom', contrasting the wrinkled, striate nectary surface with slightly sunken stomata in the flowers of 'Sampion'.
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The inheritance and durability of scab resistance in apple progenies
39-46.Views:155In order to select the appropriate parent cultivars and maintain the durability of resistance, it is important to clarify the mechanisms of inheritance of scab resistance depending on the parents. It has been known that the progeny segregation ratios based on scab-resistance do not depend only on the genotype of the resistance locus but also on the genetical makeup of the donor and recipient parents as well as on the susceptible parent.
The aim of this study has been to demonstrate what factors in the Vf, Vr and VA scab-resistant cultivars — combined with susceptible and resistant parents — affect the inheritance and durability of resistance in seedlings in their first 4 year's growing four years' growth. After inoculating apple seedlings sown in 2001 with the suspension of Venturia inaequalis (Cke.) Wint. in the greenhouse, we studied the segregation ratios of the progenies into reaction classes. Seedlings showing resistance in the greenhouse were also evaluated for scab-resistance after they had been moved to the field and had naturally been infected with the pathogen in 2002 and 2004.
The majority of our results obtained in the greenhouse test, similarly to earlier experiences, have not justified monogenic inheritance at the phenotypic level. The effect of susceptible parent cultivars on the segregation ratio of progenies have become apparent again. The high infection rate of seedlings in the field trials, which had previously exhibited varying degrees of resistance in the greenhouse test, has raised concern. Our data has raised further doubts, concerning the durability of Vf resistance in Hungary. It is assumed that the composition of natural field populations of Venturia inaequalis in Szigetcsép has changed. The complexity of Vf resistance has been confirmed. The high infection rate in the progenies derived from Vf resistant cultivars draws the attention to the importance of utilizing additional sources of resistance.
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Production of transgenic carnation with antisense ACS (1-aminocyclopropane44-carboxy late synthase) gene
104-107.Views:186Dianthus chinensis and Dianthus caryophyllus varieties were tested for shoot regeneration from leaf and petal explants and transformed with Agrobacterium tuniefaciens strains (EHA 105 and LBA 4404) harbouring an apple derived ACS cDNA in antisense orientation in order to reduce ethylene production and influence the ethylene dependant traits in carnation. After transformation regenerating shoots were selected on MS medium containing 50-75-100-125-150 mg/1 kanamycin and supplemented with 1 mg/1 BA, 0.2 mg/1 NAA. Transgene integration was proved by PCR analysis with npt II spcific primers followed by Southern hybridisation of DNA isolated from green shoots on medium containing 150 mg/1 kanamycin. Several putative transformants were subjected to RT-PCR in order to examine the npt 11 expression at mRNA level. Both the transformant and the non-transformant plants were potted into glasshouse to observe the effect of changed ethylene production on flowering time, petal senescence and vase life.
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Freeze Susceptibility of Fruit Buds in 67 Apple cultivars in Hungary
29-35.Views:147Frost damage is one of the most important risks of apple production. Outstanding importance has been attributed to the frost resistance of flower-buds as decisive sites of fruit production. Browning of plants parts and tissues exposed to natural weather adversities are considered as effects of frost. In Hungary, frost damage on flower buds of both the market and new cultivars has not been assessed earlier. Observations referring to the consequences of frost damages of over four critical years, marked by their peculiar winter and spring frost hazards. Parallel observations have been made in four sites of the growing area in the Great-Plain region. 67 apple cultivars have been assessed. Each cultivar was represented by 3 trees, which were sampled at about 1-1.5 m height over ground, where the buds or inflorescences were picked for the purpose to assess the injury. The buds and flowers are cut longitudinally and rated visually according to the extent of browning of the organs and tissues. Susceptibility of different organs of the flower (pistils and anthers) were rated separately. According to our results, most resistant to spring frosts are the following cultivars: 'Gloster', 'Granny Smith' and appreciable tolerance is attributed in 'Gala' and 'Jonathan' with derivatives. Preliminary results that among the scab resistant cultivars, `Baujade', 'Rewena', 'Liberty', `Resi' and 'Renora' are rather frost resistant. Information, lacking hitherto, is obtained upon 'Reka' and 'Reglindis' as for their increased susceptibility.
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Comparative performance of traps for the Mediterranean fruit fly Ceratitis capitata Wiedemann (Diptera: Tephritidae) baited with female-targeted or male-targeted lures
11-14.Views:216Results of trapping trials in Italy confirmed that the non-sticky CSALOMON® VARs+ funnel trap was highly efficient for the capture of Mediterranean fruit fly (Ceratitis capitata Wiedemann) (Diptera: Tephritidae), when baited with either male-targeted (trimedlure), or synthetic female-targeted (ammonium carbonate, ammonium acetate, trimethylamine, putrescine) baits. Trimedlure-baited traps caught ten times more flies (all males), than traps with synthetic female-targeted lures (which cauught predominantly females). Although less efficient, traps with the female-targeted lures had the significant advantage over trimedlure that they attracted predominantly females, so in cases when for control or experimental purposes the capture of female flies is more informative (i.e. timing of egg-laying, fertility and fecundity studies, etc.), these lures would be the best choice. The present results suggested that putrescine could be left out from female-targeted lure combinations without dramatic change in activity.
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Study on the viruses of Petunia in Hungary
55-59.Views:149Virus susceptibility of 11 varieties of vegetatively propagated petunia against 2 virus strains (TMV-C/U1 and PVYNTN) were examined. Neither resistant nor tolerant varieties of petunia were found. The virus infection of the Petunia genus was examined in Hungary. The most common pathogens were the Tobacco mosaic tobamovirus (TMV) and the Tomato mosaic tobamovirus (ToMV), but the samples also contained Alfalfa mosaic alfamovirus (AMV), Cucumber mosaic ClIC11171014171S (CMV) and Potato Y potyvirus (PVY). Potato X potexvirus (PVX) was isolated in the varieties of trailing petunia for the first time.
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Healthcare values and potential uses of the new Hungarian apple varieties on the basis on fruit analysis
25-28.Views:209Biological active compounds and valuable characteristics of some apple varieties and candidates were measured in our trials. Fruits of ’Rosmerta’, ’Hesztia’, ’Cordelia’ and ’Artemisz’ are recommended to enrich the Hungarian assortments for fresh consumption and choice of new tastes. Based on examined parameters it can be assumed that novel Hungarian resistant varieties are suitable for juice and fruit concentrate production, and due to high pectin content of their remaining pomace these varieties can be raw material of pectin production as well as they are also suitable for jam production mixed with other fruit species. Furthermore, functional food industrial product having high quality can be produced by using novel resistant varieties because of their high pectin and polyphenol content. Beside of their high market value their suitability for growing among orchard conditions is confi rmed by lower costs of production because of less plant protection treatments.
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The effect of soil mixtures of different consistence and phosphorus content in tray transplant-growing by lettuce
71-76.Views:176The transplant-growing with root balls gets more and more popular and time to time the only method even in high-quality lettuce transplant-growing. To work out the technology of transplant-growing in trays it was needed to define the accurate physical and chemical consistency of applied soils.
The transplant production in trays could become a good method in field-grown lettuce technologies. The production of transplants of good quality with this technology could be realised only by accurate soil mixtures.
The matter of transplant-growing substrates could be a low-moor turf. Its qualities could be positively influenced by adding minerals like bentonite in amount of 5 (or 10) V%.
To ensure enough phosphorus for the demands of transplants we have to add more fertilisers. The best results by lettuce we got by adding 4 kg/m3 superphosphate to the soil mixture.
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Fire blight (Erwinia amylovora) susceptibility of old Hungarian apple cultivars
35-38.Views:179The aim of the Hungarian apple breeding program started in the Department of Fruit Science was to find resistant apple cultivars against major diseases (scab, powdery mildew, fire blight). The outbreak of fire blight (Erwinia amylovora) in 1996 motivated us to search new resistant sources principally from old traditional apple cultivars. First of all, cultivars have been gathered since 1997 from Carpathia (Visk) and evaluated between 2001 and 2003. In this recent study evaluation of resistance of old Hungarian genotypes to fire blight collected from the English National Fruit Collection (Brogdale, Faversham) is presented.
13 old Hungarian apple cultivars in 2002, and 38 genotypes in 2005 have been evaluated. We used `Idared' and 'Jonathan M41' as susceptible controls and 'Liberty' and 'Remo' as resistant ones. Shoots of two-year-old potted plants were inoculated with a mixture of virulent E. amylovora isolates (Ea2, Ea60, Ea67) at a concentration of 5 x 108 cells/ml. Resistance of apple cultivars was evaluated weekly, four times after inoculation by disease severity of symptoms. Numbers of bacterial colonies in 1 cm length shoot were determined in the fourth week after infection.
8 cultivars in 2002 and 9 cultivars in 2005 displayed notable resistance to fire blight based on one-year data. Based on the coincident data of both years, out of the cultivars collected also from Carpathia ‘Pónyik', and `Sikulai' were found to be resistant and gene sources additional old Hungarian valuable apple genotypes could be selected: `Szabadkai szercsika' and `Tordai piros !davit'. The cultivar `Szemes alma' originated from Visk has proved to be recurrently resistant.
The number of bacterial cells in shoots of the investigated cultivars correlated with the severity of symptoms. With this method, which was introduced by us earlier, we can screen cultivars displaying weak visible symptoms, which cannot be proposed as a source of resistance because of their latent infection.
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The role and current state of gene reservation of medicinal and aromatic plants in Hungary an overview
19-21.Views:195As it well known the decrease of biodiversity is a large problem all over the world. In case of medicinal plants, where the huge majority of drugs are collected from natural ecosystems, the sustainable, utilization of the populations and reservation of their gene-pools has an increased interest.
In Hungary, the major background of 'in situ' reservation of medicinal plant species, their natural plant associations and ecosystems is the official protection by law. Successful examples are known for the controlled utilization of medicinal and aromatic plant species grown in protected areas. Assuring the naturally occuring high degree of biological and chemical diversity of species is a special task in this field: only maintenance of valuable intraspecific races can form the real genetic basis of natural biologically active compounds.
Maintenance of chemotaxonomical gardens and gene bank collections (seed banks, tissue banks) as 'ex situ' methods of reservation is carried out on an extended range in Hungary. As the required information on storage and maintenance of many medicinal and aromatic plant species is yet missing, exhaustive research is carried out at both genebanks in Hungary, which are specialized for medicinal plant reservation (RIMAP- Budakalász, SZIU- Budapest).
Beside the static conservation methods, 'quasi-production systems' are intended to assure an up-to-date and economically possible way of dynamic reservation with sustainable utilization.
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Malus taxa and the progenies of Malus floribunda selected in Hungary, as gene sources of resistance breeding
25-28.Views:139One of our objectives in the apple breeding program of the Department of Fruit Science, beside creating new varieties, is to search for new gene sources. After evaluating the disease resistance of Malus taxa available in Hungary, we put the promising selected individuals through further examinations. Their habit and growth vigor was observed, as well as productivity and fruit characteristics were evaluated. Malus fusca seems to be a new, promising gene source in Hungary among the examined taxa. Beside its optimal canopy, growth vigor and fruit characteristics, it has the advantage to be in distant relationship to Malus x domestica, therefore its resistance is based on a different genetic basis. SBG 1 selection of Malus spectabilis can be recommended as a new gene source for resistance breeding. The range of gene sources can further be widened by selected clones of Malus floriblunda (BA I), Malus x zumi (BA) and Malus baccata (SBG 6). An additional value of Malus taxa chosen by us is that they show resistance not only to apple scab, but to powdery mildew as well, and according to our results, they have optimal habit, acceptable productivity and good fruit quality. Nine hybrids were selected from first Malus progenies which proved to be resistant to apple scab and powdery mildew. These are valuable not only as gene sources of breeding, but as pollenizers or ornamental trees, while their decorative fruits can be used in inside decorations and flower arrangements.
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Epidemiological survey of Xanthomonas arboricola pv. juglandis and Gnomonia leptostyla on natural population of walnut (Juglans regia) in eastern Transylvania
7-9.Views:2141In Romania, walnut Juglans regia L. is an important fruit crop, although most of the fruit production comes from non-grafted walnut trees, which are natural hybrids. Breeding programs have been launched during last 30 years to develop new cultivars with uniform fruit quality. In addition, foreign cultivars have been introduced and tested to establish a valuable walnut genepool. To improve the present assortment of generative rootstocks in walnut and to examine the infestation level, a long term survey was carried out in Eastern Transylvania. The main physical characteristics of fruits and its variation to the infestation level were considered. The cumulative distribution of Xanthomonas arboricola pv. juglandis and Gnomonia leptostyla were relatively low and the maximum value was around 15%. The highest infestation of husk with X. arboricola pv. juglandis was observed for roundish forms and differences were statistically significant comparing with other phenotypes. Infestation with G. leptostyla was similar for roundish, elliptic and thwarting egg-shaped phenotypes, while the husk infestation for egg-shaped phenotypes was not observed. The walnut population studied in our experiment can be considered as a genetically valuable population. More than 20% of them have upper class quality fruits with at least or more than 50% of nutmeat. Do to the large scale climate variation in Eastern Transylvania and the high humidity favourable for pathogen infestations, these population can be considered resistant and well adapted to abiotic and biotic factors.
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Salt tolerance of sweet pepper seedlings
62-66.Views:150Laboratory germination tests have been made with three white fruit pepper varieties and with one spice pepper in filter paper rolls wetted with KCl solutions of different concentration. Parallel tests have been conducted with the other species (lettuce, tomato, kohlrabi) to compare the salt tolerance of paprika with that of other vegetable crops.
In greenhouse, the action of KCl has been investigated with transplants raised in soil mixture, in rockwool and with seedlings transplanted from rockwool into soil mixture. Like the trials in the laboratory, the experiments in soil mixture have been made with other plant species, too.